Transmission NT on RN6, can't add torrent via Remote GUI

Hi Guys - I'm bashing my head against the wall trying to get Transmission Remote GUI set up after migrating from OS4 to OS6. I've got Transmission NT installed, and it's working fine. Where I'm having troubles is with the Remote GUI - which I previously had working fine under OS4.

I've gotten as far as being able to connect Remote GUI to the daemon, but I error out when trying to add new torrents. The way it behaves suggests I'm trying to save into the wrong spot / some folder Transmission doesn't have permissions too - but I'm copy / pasting the paths in... In fact, existing torrents added via the web client work just fine with the same path I'm trying to hit.

I'm sure there's something basic like a backslash I'm missing, but would appreciate any pointers.

The error that I'm getting;

Here are my path mappings - which work when I click to browse to the folder to save to;

And when I'm adding a torrent - the folder I'm trying to save to;

My Remote GUI login settings;

And a snapshot from WinSCP showing the folder permissions that should be wide open;